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United States Patent |
5,216,394
|
Konishi
,   et al.
|
June 1, 1993
|
Dielectric multi-line resonator including a coupling conductor line
mainly inductively coupled to a resonator conductor line
Abstract
For removing the variation of resonant frequency of the 1/4 .lambda.g
coaxial resonator, which is caused by the external connection as a result
of conventional capacitive coupling, a 1/4 .lambda.g line having both ends
opened is coupled to the 1/4 .lambda.g resonant line having one end
shorted through distributed inductive coupling, so as to provide a basic
structure of the dielectric resonator of the invention, which can be
arranged in usual various types of circuits such as filters, multiplexers
and the like with excellent and stable performances.
Inventors:
|
Konishi; Yoshihiro (Sagamihara, JP);
Hikuma; Hideo (Chiba, JP);
Fujiwara; Hideki (Ichikawa, JP)
|
Assignee:
|
Uniden Corporation (Ichikawa, JP)
|
Appl. No.:
|
732766 |
Filed:
|
July 19, 1991 |
Current U.S. Class: |
333/222; 333/134; 333/136; 333/206 |
Intern'l Class: |
H01P 007/04; H01P 005/12; H01P 001/205 |
Field of Search: |
333/134,202,206,207,222,136,219
|
References Cited
U.S. Patent Documents
4410868 | Oct., 1983 | Meguro et al. | 333/202.
|
Foreign Patent Documents |
0364931 | Apr., 1990 | EP | 333/202.
|
0165103 | Aug., 1985 | JP | 333/202.
|
0230703 | Nov., 1985 | JP | 333/222.
|
0135002 | Jun., 1988 | JP | 333/222.
|
0196901 | Aug., 1989 | JP | 333/202.
|
0177701 | Jul., 1990 | JP | 333/202.
|
Primary Examiner: Pascal; Robert J.
Assistant Examiner: Ham; Seung
Attorney, Agent or Firm: Stevens, Davis, Miller & Mosher
Claims
What is claimed is:
1. A dielectric multiline resonator comprising:
a dielectric material block which has top and bottom faces which face each
other in parallel relationship and are spaced apart from each other
substantially by one-fourth a wavelength of a wave to be guided thereby
and at least mostly conductive surrounding side faces which are
perpendicular to said top and bottom faces, and
a plurality of conductive lines which are provided through said dielectric
material block, which have respective axes which are perpendicular to said
top and bottom faces of said dielectric material block and which are
consecutively coupled with each other inductively through no mediation,
wherein at least one conductive line of said plurality of conductive line
is a resonant line having one end electrically connected with said
conductive side faces and another end open-circuited relative to all other
conductive components of said resonator, at least one other conductive
line of said plurality of conductive lines is a coupling line and is
adjacent to and primarily inductively coupled to said resonant line, both
ends of said coupling line being open-circuited relative to all other
conductive components of the resonator and one of said ends being for
connection with external circuits, so as to be inductively coupled with
said external circuits.
2. A dielectric multiline resonator as claimed in claim 1, wherein said
resonant line is formed by a conductive inside wall face of a hole bored
through said dielectric material block substantially perpendicularly to
said top and bottom faces, said bottom face of said dielectric material
block is conductive and electrically connected with said conductive side
faces and said conductive inside wall face.
3. A dielectric multiline resonator as claimed in claim 1, wherein said
coupling line is formed by a conductive portion of an inside wall face of
a hole bored through said dielectric material block substantially
perpendicularly to said top and bottom faces, said conductive portion
extending from the top face at least beyond a midpoint of said hole.
4. A dielectric multiline resonator as claimed in claim 2, wherein said
coupling line is formed by a conductive portion of an inside wall face of
a hole bored through said dielectric material block substantially
perpendicularly to said top and bottom faces, said conductive portion
extending from the top face at least beyond a midpoint of said hole, said
conductive portion being not electrically connected to said conductive
bottom face.
5. A dielectric multiline resonator as claimed in claim 2, wherein said
coupling line is provided by a conductive inside wall face of a hole bored
through said dielectric material block substantially perpendicularly to
said top and bottom faces, said bottom face including a non-conductive
portion which closely surrounds a conductive aperture of said hole.
6. A dielectric multiline resonator as claimed in claim 2, wherein said
resonant line is formed by a conductive inside wall face of a hole bored
through said dielectric material block close to said side face and
substantially orthogonal to said top and bottom faces, a portion of said
side face which is parallel to said resonant line being non-conductive,
and said coupling line is formed by a conductive strip line which is
provided within said non-conductive portion of said side face in parallel
with said resonant line.
7. A dielectric multiline resonator as claimed in claim 1, wherein two of
said plurality of conductive lines are operated as a said coupling line,
said two of said plurality of conductive lines being coupled to said
resonant line as input and output lines respectively, so as to operate
said resonator as a bandpass filter.
8. A dielectric multiline resonator as claimed in claim 1, wherein said
coupling line is operated as at least one of an input line and an output
line and said resonant line is operated as a trap filter.
9. A multiplexer, comprising:
a dielectric material block which has top and bottom faces which face each
other in parallel relationship and are spaced apart from each other
substantially by one-fourth a wavelength of a wave to be guided thereby
and at least mostly conductive surrounding side faces which are
perpendicular to said top and bottom faces, and
a plurality of conductive lines which are provided through said dielectric
material block and which have respective axes which are perpendicular to
said top and bottom faces of said dielectric material block and which are
consecutively coupled with each other inductively through no mediation,
wherein a first pair of adjacent ones of said conductive lines and a second
pair of adjacent ones of said conductive lines are resonant lines each
having one end electrically connected with said conductive side face and
another end open-circuited relative to all other conductive components of
said multiplexer, a first one, a second one and a third one of said
conductive lines are coupling lines primarily inductively coupled to said
resonant lines and having both ends open-circuited relative to all other
conductive components of said multiplexer, said first one, said first pair
of conductor lines, said second one, said second pair of conductor lines
and said third one being arrayed in that order, said first one and said
first pair of conductor lines constituting a first bandpass filter and
said third one and said second pair of conductor lines constituting a
second bandpass filter having a different resonant frequency from that of
said first bandpass filter, said first one and said third one operating as
output lines and said second one operating as an input line in common to
said first bandpass filter and said second bandpass filter.
10. A power splitter, comprising:
a dielectric material block which has top and bottom faces which face each
other in parallel relationship and are spaced apart from each other
substantially by one-fourth a wavelength of a wave to be guided thereby
and at least mostly conductive surrounding side faces which are
perpendicular to said top and bottom faces, and
a plurality of conductive lines which are provided through said dielectric
material block and which have respective axes which are perpendicular to
said top and bottom faces of said dielectric material block and which are
consecutively coupled with each other inductively through no mediation,
wherein a first pair of adjacent ones of said conductive lines and a second
pair of adjacent ones of said conductive lines are resonant lines each
having one end electrically connected with said conductive side face and
another end open-circuited relative to all other conductive components of
said power splitter, a first one, a second one and a third one of said
conductive lines are coupling lines primarily inductively coupled to said
resonant lines and having both ends open-circuited relative to all other
conductive components of said power splitter, said first one, said first
pair of conductor lines, said second one, said second pair of conductor
lines and said third one being arrayed in that order, said first one and
said first pair of conductor lines constituting a first bandpass filter
and said third one and said second pair of conductor lines constituting a
second bandpass filter having a same resonant frequency as that of said
first bandpass filter, said first one and said third one operating as
output lines and said second one operating as an input line in common to
said first bandpass filter and said second bandpass filter.
Description
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a dielectric multi-line resonator,
including a coaxial resonator providing a one-fourth wavelength line
having one end opened and the other end shorted through a dielectric
material block surrounded by an earthed conductor, which is used
principally for UHF band, particularly for remarkably reducing the
variation of resonant frequency in comparison with the conventional one,
which is caused by external connection.
(2) Description of the Prior Art
For coupling a coaxial resonator, which is basically formed by providing a
one-fourth wavelength line having one end opened and the other end shorted
through a dielectric material block surrounded by an earthed conductor,
with an external circuit, a capacitive coupling means has been almost
exclusively employed mainly by reason of the readiness of composition and
manufacture. Concretely speaking, as shown in FIG. 1A, in a typical
coaxial resonator formed of an inside wall face conductor 4 of a central
hole 3 provided through a dielectric material block 2 of one-fourth
wavelength height, which is surrounded by side face conductors 1a and a
bottom face conductor 1b, a terminal conductor 6 supported by an insulator
5 is inserted into the upper end portion of the central hole 3, and hence
the external terminal coupling is attained by the capacity between the
side face conductor 4 operated as the resonant line and the terminal
conductor 6. In the other case, as shown in FIG. 1B, in the coaxial
resonator arranged the same as described above, another terminal conductor
8 is inserted into a small hole 7 provided in the upper end portion of the
dielectric material block 2 close by the side face conductor 4, and hence
the external terminal coupling is attained by the capacity between both of
those conductors 4 and 8.
However, the above mentioned capacitive external coupling to the coaxial
resonator has a difficulty such that the variation of resonant frequency
in response to the extent of coupling to external circuits is extensive,
and further precise manufacturing is required by the dependency of the
coupling extent on shape and size, in spite of the advantage that the
structure is simple, with resulting facilitated manufacturing and further
stable coupling can be attained.
On the other hand, with regard to the resonant frequency variation
responding to the coupling extent, the inductive coupling based on coils
or the like is more tolerant and hence the coupling to external circuits
can be stabilized thereby. However, the conventional structure thereof has
difficulties such that the manufacturing takes much time and much labor
and hence is not suited for mass-production.
SUMMARY OF THE INVENTION
An object of the present invention is to remove the above difficulties and
to provide a dielectric multiline resonator basically formed of a coaxial
resonator, the structure of which is simple and hence is suited for mass
production, and in which the resonant frequency variation caused by
coupling to external circuits is removed by adopting a mainly inductive
coupling means.
A dielectric multiline resonator according to the present invention is
basically arranged such as a coupling conductor line is inserted into a
dielectric material block of a coaxial resonator close in parallel with a
central resonant conductor line in a state of both ends opened, so as to
obtain a mainly inductive coupling to the central resonator conductor
line.
In other words, the dielectric multiline resonator of the present invention
is featured by comprising
a dielectric material block which has top and bottom faces facing to each
other in parallel apart from each other substantially by one-fourth of
guided wavelength concerned and conductive surrounding side faces being
perpendicular to said top and bottom faces, and
a plurality of conductive lines which are provided through said dielectric
material block with respective axes which are perpendicular to said top
and bottom faces of said dielectric material block,
wherein at least one of said plurality of conductive lines, one ends on the
same one side of which are electrically connected with said conductive
side faces and the other ends on the other side are opened, are operated
as resonant lines, while at least the other one of said plurality of
conductive lines, which are adjacent and coupled to said resonant lines
respectively and both ends of which are opened together, are operated as
coupling lines, open ends on the other side of which are prepared to be
connected with external circuits.
Consequently, in the dielectric multiline resonator of the present
invention, a coaxial resonator having a simple and readily manufactured
structure, in which the resonant frequency is not varied by coupling to
external circuits and the setting of input and output impedances and the
small-sizing are ready, can be readily realized.
BRIEF DESCRIPTION OF THE DRAWINGS
For the better understanding of the invention, reference is made to the
accompanying drawings, in which:
FIGS. 1A and 1B are cross-sectional views showing conventional manners of
external coupling to a coaxial resonator respectively, as already
mentioned;
FIGS. 2A, 2B and 2C are a cross-sectional view, a perspective view and an
equivalent circuit diagram showing a basic structure of a dielectric
multiline resonator according to the present invention respectively;
FIGS. 3A, 3B and 3C are diagrams showing the operational principle of
external coupling according to the present invention in order;
FIGS. 4A and 4B are a perspective view and an equivalent strip line diagram
showing an example of a band pass filter according to the present
invention respectively;
FIG. 5 is a cross-sectional plan and a cross-sectional elevation showing
another example of the same;
FIGS. 6A and 6B are a perspective view and an equivalent strip line diagram
showing an example of a multiplexer according to the present invention
respectively; and
FIGS. 7A and 7B are a perspective view and an equivalent strip line diagram
showing an example of a trap filter according to the present invention,
respectively.
Throughout different views of the drawings: 1a is a side face conductor; 1b
is a bottom face conductor; 2 is a dielectric material block; 3 is a
central hole; 4 is an inside wall face conductor (resonant line); 5 is an
insulator; 6, 8 are terminal conductors; 7 is a small hole; 9a is an
inside wall face conductor (coupling line); 9b is a coupling line; 10 is a
non-conductive portion; R is a resonant line; C is a coupling line; L is a
load; S is a signal source; M is a meter; T is a trap line.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various examples of the dielectric multiline resonator according to the
present invention will be described hereinafter in detail.
A basic structure of a coaxial resonator according to the present
invention, which corresponds to the conventional one as shown in FIGS. 1A
and 1B, is shown in FIGS. 2A, 2B and 2C.
As shown in FIG. 2A, in the basic structure according to the present
invention, in which a typical coaxial resonator formed of a inside wall
face conductor 4 of a central hole 3 provided in a one-fourth wavelength
height dielectric material block 2 surrounded by a side face conductor 1a
and a bottom face conductor 1b is applied with the present invention, a
hole 9a passing through the dielectric material block 2 close to and
parallel with the inside wall face conductor 4 of the central hole 3,
which is operated as the resonant line, is provided in the block 2, and is
operated as a coupling line by inserting a conductor line 9b therethrough
or by making the inside wall face conductive similarly to the resonant
line 4. On this occasion, a portion 10 of the bottom face conductor 1b,
which surrounds an aperture of the perforating hole 9a, is made
non-conductive in an appropriate range, so as to provide an inside wall
face conductor 9c (see FIGS. 2B, 4A, 5, 6A and 7A) of one-fourth
wavelength height situated in a state of both ends opened.
For making the inside wall face of hole 9a conductive, silver paste is
coated and fused thereon similarly to the usual arrangement in this case.
Moreover, it is preferable to spread the coated film within the
non-conductive portion 10 of the bottom face conductor 1b around the
aperture of the perforating hole 9a. In this connection, the impedance of
the coupling line formed of the inside wall face conductor 9c is varied by
the shape and the size of the perforating hole 9a , the distance from the
resonant line 4 and the side face conductor 1a or the like, and further
can be appropriately set up, for instance, by mixing resistive material
into silver paste and hence the impedance matching to the coupled external
circuit can be attained.
The open end of the coupling line provided by inside wall face conductor 9c
on the same side as that of the resonant line 4, as shown in FIG. 2B, is
coupled to external circuits by terminating through a load L corresponding
to the characteristic impedance Zo thereof.
In a distributed coupling obtained between the resonant line 4 formed of
one-fourth wavelength conductor having one end opened and the other end
shorted and the coupling line formed of the same having both ends opened,
the capacitive coupling is dominant along the upper half thereof, while
the inductive coupling is dominant along the lower half thereof.
Consequently, according to the present invention, the object of which is
to remove the resonant frequency variation caused by the external coupling
through the employment of inductive coupling to the resonant line, the
length of the coupling line should be set beyond the midpoint from the
open end of the resonant line 4, that is, longer than one-eighth
wavelength. However, it is preferable in practice to select the one-fourth
wavelength, so as to minimize the resonant frequency variation caused by
the external coupling.
An equivalent circuit of the above-mentioned basic structure of the
resonator according to the present invention, consists of a series
connection of a parallel resonant circuit equivalent to the resonant line
4 and a series resonant circuit equivalent to the coupling line, as shown
in FIG. 2C. The capacitive variation of one of those resonant circuit
impedances and the inductive variation of the other thereof are canceled
by each other and hence the impedance variation caused by the external
coupling is removed. As a result, an excellent wideband external coupling
performance can be attained.
The above described basic structure of the resonator according to the
present invention is equivalent to a strip line structure as shown in FIG.
3A and hence is operated similarly as the strip line structure in which a
coupling line C having a length l which exceeds one-eighth wavelength
disposed close to and in parallel with a resonant line R having a
one-fourth wavelength of one end shorted in a state such as respective
open ends are arranged alternately with each other.
In the one fourth wavelength resonant line having one end shorted and the
other end opened, an inductive potential distribution is obtained on the
shorted end side from the midpoint, while a capacitive potential
distribution is obtained on the open end side therefrom. As a result, in a
state wherein the resonant line R and the coupling line C are arranged
close to and in parallel to each other with respective open ends
alternately directed, as shown in FIG. 3B, respective capacitive and
inductive potential distributions alternately arranged with regard to the
midpoint of one-eighth wavelength interact throughout those lines and
hence the wide band mutual coupling is obtained. On the contrary, in a
state wherein those lines R, C are arranged close in parallel to each
other with respective open ends directed in the same direction as shown in
FIG. 3C, respective capacitive and inductive potential distributions repel
each other and hence any mutual coupling cannot be obtained.
In a dielectric multiline resonator formed by combining plural conductor
lines similarly to the usual arrangement, under the application of the
resonator according to the present invention, which has the above
mentioned basic structure with good coupling property, an excellent
performance in comparison with conventional resonators of the same kind
can be obtained and further the structure can be simplified and
small-sized.
Several examples of a dielectric multiline resonator according to the
present invention will be described hereinafter by referring to respective
drawings.
An example of a bandpass filter, a perspective view of which is shown in
FIG. 4A and an equivalent strip line diagram of which is shown in FIG. 4B,
is arranged such that two coupling lines 9c-1(C1) and 9c-2(C2) are closely
arranged in front and rear of a resonant line 4(R) as input and output
lines respectively, so as to obtain a single peak pass band.
Another example of the same, a cross-sectional plan view and a
cross-sectional elevation view of which are shown in FIG. 5, is arranged
such that two coupling lines 9c-1 and 9c-2 are closely arranged in front
and rear of two mutually coupled resonant lines 4-1 and 4-2 as input and
output lines respectively, so as to obtain a double peak bandpass. In this
connection, the coupling between two resonant lines 4-1, 4-2 consists, in
general, of capacitive or inductive coupling. However, it is omitted in
the drawings similarly as in the subsequent drawings.
A multiplexer, a perspective view of which is shown in FIG. 6A and an
equivalent strip line diagram is shown in FIG. 6B, is arranged such that
respective two resonant lines 4-1,2 and 4-3,4, which have respective
resonant frequencies f.sub.1 and f.sub.2 and are coupled in order
respectively, are closely arranged in front and rear of a coupling line
9c-2 operated as an input line respectively, and further, in front and
rear of those resonant lines, two coupling lines 9c-1 and 9c-3 are closely
arranged as output lines respectively, so as to separate from each other
two high frequency powers, which have respective frequencies f.sub.1 and
f.sub.2, and are mixed with each other and supplied through the common
input line 9c-2 and to take out those powers through output lines 9c-1 and
9c-3 respectively.
However, in case that resonant frequencies f.sub.1 and f.sub.2 are
identical to each other, it is operated as a power splitter. In this
connection, the height of the dielectric material block 2, or, the length
of the resonant line R, is naturally set up to one fourth of respective
wave lengths in response to the difference between those wavelengths.
An example of a trap filter, a perspective view of which is shown in FIG.
7A and an equivalent strip line diagram of which is shown in FIG. 7B, is
arranged such that, on the opposite side of an input coupling line 9c
arranged close by a resonant line 4 which has a single peak pass-band,
another resonant line 4t, which has a resonant frequency corresponding to
the stopping or trapping frequency ft, is closely arranged, and further, a
portion of the side face conductor 1a, which portion is close by the
bandpass resonant line 4, is made non-conductive, so as to operate a strip
line 12 provided on the non-conductive portion concerned similarly as the
coupling line 9b in the basic structure as shown in FIG. 2A as an output
line.
As is apparent from the above description, according to the present
invention, the following special effect can be obtained.
The variation of the resonant frequency in the dielectric multiline
resonator basically consisting of the coaxial resonator, which variation
is caused by the coupling to external circuits, can be remarkably reduced,
and hence the wideband coupling can be stably attained.
Moreover, the structure of the external coupling means is considerably
simplified in comparison with the conventional means, and hence can be
readily manufactured, so as to readily obtain products having uniform
properties in mass-production.
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